df4c05f834
When this class was written, all swipes in the shell were vertical, so it made sense to make the default orientation vertical. This isn't the case anymore, thus pass make it mandatory to specify orientation when creating a tracker. Change the property default values to horizontal as well to match Clutter instead of the old shell design. Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1731>